The invention relates to a method for producing bristle areas for brushes, particularly toothbrushes, with the bundles of bristles being separated from a bristle supply and transported via a gas or air flow and inserted into perforations of a central plate as well as an apparatus for producing bristle areas for brushes, comprising a bristle supply and an apparatus for removing individual bundles of bristles from the bristle supply as well as a transport apparatus for transporting the bundles of bristles into perforations of a central plate via a gas or air flow.
Such a method including an apparatus are known, for example from EP 0 405 204 B1. Here, several bundles of filaments are transported via hoses into a carrier plate. Subsequently the bundles of filaments are connected to a thermoplastic carrier plate by way of melting and/or injection molding with a plastic material to form a brush head. The fill level of the perforations accepting the bundles of filaments is relatively low, due to the supply of the bundles of bristles using a gas or air flow, because the supply lines for transporting the bundles via a gas or air flow allow only a limited fill level without the lines becoming clogged or individual filaments being left behind in the supply line during transportation. The fill level represents the ratio of the cross-section of the perforation in a plate in reference to the total of cross-sections of all filaments held in this perforation. The low fill level leads to the consequence that during the injection molding of the filaments with jets of high pressure injection material passing through the filaments and becoming visible at the surface of the brush, which is unappealing or may render the brush useless.
DE 4330171 A1 describes a process and an apparatus for the production of brushes, in which bristle bundles are connected with a brush body in an injection molding process. In order to reduce the chances of the injection molding material passing into the region of the bristle bundles, bristle bundles held in carrying perforations of a bristle bundle holder are transferred with the help of a transport punch from the holder and into a sealing perforated plate, that has a perforation field corresponding to the perforation field of the bristle bundle holder, in which the cross-sections of the through perforations are slightly smaller so that the bristle bundles are somewhat sealed. The thereby sealed bristle bundles are carried to an injection molding machine and there injection molded.
In the brush manufacturing machine of DE 442057 A1, bristle bundles are positioned in perforations of a perforated plate located before a form plate, and through pressure pins are transferred to the bristle bundle receiving holes of a form plate. The bristle bundle receiving holes have at least sectionally a reduced cross-section in comparison to the perforations in the perforated plate, in order to seal the bristle bundles for molding.
A similar arrangement is provided in DE 29712554 U1. Also here the bristle bundles are transferred from a transport plate to a sealing plate using pressure pins in order to press them together.
Also in the method according to DE 10108339 A1. bristle bundles are impinged by stamps in order to be carried from a packing plate to a perforated plate. In that the holes in the packing plate are funnel shaped, the bristle bundles are sealed during transfer from the packing plate to the perforated plate.
In DE 4320171 A1, as well as in DE 4420757 A1, DE29712554 and DE 10108339, the bristle bundles are not carried by a gas or air flow to the bristle bundle holder. Here, this allows the individual bristle filaments to be conveyed more quickly than before or for transfer to the central plate individual bristle filaments can be held back, so that the bristle filaments can be arranged in the central plate offset from one another in a longitudinal direction.